Carpooling (also known as car-sharing, ride-sharing,
lift-sharing and covoiturage), is the sharing of car journeys so that more than one person travels in a car.

By having more people using one vehicle, carpooling reduces each person's travel
costs such as fuel costs, tolls and the stress of driving. Carpooling is also seen as a more environmentally friendly
and sustainable way to travel as sharing journeys reduces carbon emissions, traffic congestion on the roads, and the need
for parking spaces. Authorities often encourage carpooling, especially during high pollution periods and high fuel prices.

How Carpooling Works

Drivers and passengers offer and search for journeys through one of the several
mediums available. After finding a match they contact each other to arrange any
details for the journey(s). Costs, meeting points and other details like space
for luggage are agreed on. They then meet and carry out their shared car
journey(s) as planned.

Carpooling is commonly implemented for commuting but is increasingly popular for longer one-off journeys, with the formality and
regularity of arrangements varying between schemes and journeys.

Carpooling is not always arranged for the whole length of a journey. Especially
on long journeys, it is common for passengers to only join for parts of the
journey, and give a contribution based on the distance that they travel. This
gives carpooling extra flexibility, and enables more people to share journeys
and save money.

Today most carpooling is organized thanks to fast-emerging online marketplaces
that allow drivers and passengers to find a travel match and make a secured
transaction to share the planned travel cost. Like other online marketplaces,
they use community-based trust mechanisms, such as user-ratings, to create an
optimal experience for users.

Arrangements for carpooling can be made through many different mediums,
including: